c++ - 使用 LodePNG 加载 GLFWImage

Question

更新:我没有分配 GLFWimage 的 width 和 height，这导致它没有出现。

我正在尝试使用 lodePNG 将图像加载到 GLFW 中以用作纹理或图标。

我使用的函数与显示的非常相似 here .

这是我的代码:

#include <iostream>
#include <lodepng/lodepng.h>

unsigned char* decodeOneStep(const char* filename) {
    unsigned error;
    unsigned char* image;
    unsigned width, height;

    error = lodepng_decode32_file(&image, &width, &height, filename);
    if (error) printf("error %u: %s\n", error, lodepng_error_text(error));

    return image;
}

稍后(在创建窗口及其上下文之后)，我调用此函数来分配 GLFWImage 获取的 unsigned char* 来分配窗口图标如下:

GLFWimage icons[1];
unsigned char* imageData = decodeOneStep("assets/icons/icon.png");
icons[0].pixels = imageData;

// window is a GLFWwindow*, 1 is the image count
glfwSetWindowIcon(window, 1, icons);

编译并运行良好，但我的窗口图标没有改变(它仍然是默认图标)。

这是我要加载的图像(它是 48x48，lodepng 可以正确识别)

我还 cout 编辑了 imageData 并得到了这个，它看起来像通用的 png 数据(尽管我不确定这是否有用):

                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
                                                                                                                        
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不幸的是，我不知道如何解决这个问题，所以我们将不胜感激。

tl;dr:为什么 glfwSetWindowIcon 没有将我的窗口图标更改为使用 lodepng 加载的图像？

Answer 1

This compiles and runs fine, but the icon of my window hasn't changed (it's still the default one).

可能是因为您传递给 glfwSetWindowIcon 的数据处于无效状态。

您几乎做对了，但是您没有指定要传递给 glfwSetWindowIcon 的图像的宽度或高度，因此，您重新传递垃圾数据。最佳情况下，这些值对 GLFW 无效，并且数据被忽略。最坏的情况是，值不正确但技术上有效，您会遇到缓冲区溢出和程序崩溃。

通过确保您的 decodeOneStep 函数返回所有相关内容来解决您的问题:

GLFWImage decodeOneStep(const char* filename) {
    unsigned error;
    GLFWImage image;

    error = lodepng_decode_32_file(&(image.pixels), &(image.width), &(image.height), filename);
    if (error) printf("error %u: %s\n", error, lodepng_error_text(error));

    return image;
}

//............
GLFWimage icons[1];
icons[0] = decodeOneStep("assets/icons/icon.png");

// window is a GLFWwindow*, 1 is the image count
glfwSetWindowIcon(window, 1, icons);

由于您只传递一张图像，顺便说一下，我们可以使这段代码更简单一些:

GLFWimage icon = decodeOneStep("assets/icons/icon.png");
glfwSetWindowIcon(window, 1, &icon);